Statistical analysis
Categorical data are presented as frequencies and percentages, and
quantitative data are provided as median and interquartile range (IQR).
Demographic, clinical and outcome variables were compared between the
two groups of patients, using Fisher’s exact test for qualitative
variables and Mann-Whitney U test for quantitative variables. The
comparisons were carried out for all patients and by age group (younger
than 1 year, 1 to 9 years and 10 years or older).
We estimated the crude and adjusted odds ratio and 95% confidence
intervals (CI) for death and invasive mechanical ventilation using
logistic regression. The final model included age a priori; other
variables (sex, nutritional status, comorbidities) were included based
on reverse stepwise regression (i.e., stopping rule Wald test
<0.20). All analyses were performed using STATA 15 statistical
package. (College Station, TX, USA: StataCorp).